1. Field of the Disclosure
Embodiments of the present disclosure generally relate to the field of binaural and stereophonic audio signal processing and, more particularly, to optimizing audio signals for reproduction over head-mounted speakers, such as stereo earphones.
2. Description of the Related Art
Stereophonic sound reproduction involves encoding and reproducing signals containing spatial properties of a sound field using two or more transducers. Stereophonic sound enables a listener to perceive a spatial sense in the sound field. In a typical stereophonic sound reproduction system, two “in field” loudspeakers positioned at fixed locations in the listening field convert a stereo signal into sound waves. The sound waves from each in field loudspeaker propagate through space towards both ears of a listener to create an impression of sound heard from various directions within the sound field.
Head-mounted speakers, such as headphones or in-ear headphones, typically include a dedicated left speaker to emit sound into the left ear, and a dedicated right speaker to emit sound into the right ear. Sound waves generated by a head-mounted speaker operate differently from the sound waves generated by an in field loudspeaker, and such differences may be perceptible to the listener. The same input stereo signal can produce different, and sometimes less preferable, listening experiences when output from the head-mounted speakers and when output from the in field loudspeakers.